Copper ions are known to be effective against the growth of algae. In the past water-soluble copper compounds, such as copper sulfate, have been used extensively as algaecides. Copper ions released by copper sulfate when added to water, react with carbonates or bicarbonates found in water to produce insoluble copper compounds which precipitate and cause turbidity or cloudiness in the treated water. If excessive amounts of insoluble copper compounds settle out, the compounds can form a sludge, which in the case of a lake or stream, may tend to destroy the fish life or zooplankton which is essential as fish food.
To overcome the problems associated with the use of copper sulfate, a complex formed by the reaction of copper sulfate and an alkanolamine, as disclosed in U.S. Pat. No. 2,734,028, has been used and has achieved wide success as an algaecide. A complex of this type has the ability to maintain the copper ions in solution, even when the algaecide is added to alkaline water containing high concentrations of carbonates or bicarbonates, as well as soft water situations.
It has been found that a copper complex of the type disclosed in U.S. Pat. No. 2,734,028 tends to decompose when subjected to sunlight and/or warm temperatures resulting in a precipitation of copper, thereby removing the toxic copper ions from solution and decreasing the effectiveness of the complex as an algaecide. To avoid the problems associated with the use of the complex derived from copper sulfate, a copper complex has been prepared using water insoluble copper compounds as disclosed in U.S. Pat. No. 3,930,834. In this latter patent the complex is formed by initially reacting an insoluble copper compound with an acid in aqueous solution to dissociate the copper ions and thereafter chelating the released copper ions to form the complex.
The copending U.S. patent application Ser. No. 700,335, filed June 28, 1976 now abandoned, discloses an improved method of preparing a copper complex from water insoluble copper compounds in which the copper compound is reacted with a chelating material, preferably an alkanolamine. The chelating material acts to solubilize and chelate the copper compound to form the copper complex.
Ammonium quaternary compounds are known for their fungicidal, bacteriacidal and algaecidal properties and have been used in the past for controlling the growth of pathogenic microorganisms in hospitals, dairies, laundries, restaurants, and the like, as well as being used to control algae in water treating systems and cooling towers.